| Re: Correlate and NAN [message #23155] |
Mon, 08 January 2001 10:24  |
btt
Messages: 345
Registered: December 2000
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Senior Member |
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Thanks Pavel and Andy,
I have deNANed the data as you suggested.
Ben
Andy Loughe wrote:
> Why not simply perform the correlation on a subset of the larger arrays,
> that portion with the NaNs removed? Something like:
>
> indices = [ where( finite(dataset1) eq 1 ), where( finite(dataset2) eq 2
> ) ]
>
> common_indices = indices( UNIQ(indices, sort(indices)) )
>
> Result = CORRELATE( dataset1(common_indices), dataset2(common_indices)
> )
>
> Ben Tupper wrote:
>>
>> Hello,
>>
>> I have two datasets that I would like to correlate using the CORRELATE
>> function. Each dataset has some members flagged as NANs; the NANs are
>> not neccessarily coincident. The online documentation makes no mention
>> of NAN-handling, but the procedure in the lib directory indicates (see
>> modifications history) that it handles NANs (although there is no
>> keyword for it). It doesn't really handle NANs the way I expect it
>> to. For example, repeated calls to the TOTAL function don't set the
>> keyword NAN, so TOTAL doesn't check for NANs.
>>
>> I'm not sure if it is reasonable to involve NANs in a correlation... but
>> it seems reasonable to request that the routine ignore NANs in the input
>> arguments.
>>
>> Is there a simple solution to this NAN-jam?
>>
>> Thanks,
>>
>> Ben
>>
>> --
>> Ben Tupper
>> Bigelow Laboratory for Ocean Sciences
>> 180 McKown Point Rd.
>> W. Boothbay Harbor, ME 04575
>> btupper@bigelow.org
>
> --
> Andrew Loughe =====================================================
> NOAA/OAR/FSL/AD R/FS5 | email: loughe@fsl.noaa.gov
> 325 Broadway | wwweb: www-ad.fsl.noaa.gov/users/loughe
> Boulder, CO 80305-3328 | phone: 303-497-6211 fax: 303-497-6301
--
Ben Tupper
Bigelow Laboratory for Ocean Sciences
180 McKown Point Rd.
W. Boothbay Harbor, ME 04575
btupper@bigelow.org
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